Question

use what you learned about mendel’s experiments to answer the following questions. studying one trait at a time ensures that multiple are not changing simultaneously. give one reason mendel chose pea plants for his experiment.

Explanation:

For the first blank: In Mendel's experiments, studying one trait at a time is to control variables. The key term here is "variables" (specifically "factors" or "traits" related to the experiment, but "variables" fits as it refers to the elements being tested; in Mendelian genetics, when studying one trait, we ensure multiple variables/traits aren't changing to isolate the effect of that one trait).

For the second part (reason for choosing pea plants): Pea plants have several suitable characteristics. One common reason is that they have easily observable and distinct traits (like flower color, seed shape), they reproduce quickly, and they can self - pollinate or be cross - pollinated easily, allowing Mendel to control the breeding process. A concise reason is that pea plants have distinct, heritable traits and can be easily manipulated for breeding (e.g., self - pollination and cross - pollination are easy to control).

Answer:

First blank: variables (or "factors", "traits" can also be acceptable in context)
Reason for pea plants: Pea plants have distinct, heritable traits (e.g., flower color, seed shape), reproduce quickly, and allow easy control of pollination (self - or cross - pollination). (A specific concise reason: Pea plants have easily observable and distinct traits, and their pollination can be controlled.)